Method for hydrogenating benzene polycarboxylic acids or derivatives thereof by using a catalyst containing macropores

ABSTRACT

A process for hydrogenating a benzenepolycarboxylic acid or a derivative thereof or a mixture of two or more thereof by bringing the benzenepolycarboxylic acid or the derivative thereof or the mixture of two or more thereof into contact with a hydrogen-containing gas is carried out in the presence of a catalyst which comprises as active metal at least one metal of transition group VIII of the Periodic Table alone or together with at least one metal of transition group I or VII of the periodic table applied to a support which contains macropores with the proviso that if dimethyl terephthalate is hydrogenated, the hydrogenation using a catalyst which comprises as active metal ruthenium either alone or together with at least one metal of transition group I, VII or VIII of the Periodic Table applied to a support, where the support has a mean pore diameter of at least 50 nm and a BET surface area of at most 30 m 2 /g and the amount of the active metal is from 0.01 to 30% by weight, based on the total weight of the catalyst, and the ratio of the surface areas of the active metal and the catalyst support is less than 0.05, and/or 
     a catalyst which comprises as active metal ruthenium either alone or together with at least one metal of transition group I, VII or VIII of the Periodic Table in an amount of from 0.01 to 30% by weight, based on the total weight of the catalyst, applied to a support, where from 10 to 50% of the pore volume of the support is formed by macropores having a pore diameter in the range from 50 nm to 10,000 nm and from 50 to 90% of the pore volume of the support is formed by mesopores having a pore diameter in the range from 2 to 50 nm, where the sum of the pore volumes adds up to 100%, is excluded, and novel hydrogenation products, obtainable by hydrogenating benzenepolycarboxylic acid (derivatives) as well as their use as plasticizers in plastics.

The present invention relates to a process for hydrogenatingbenzenepolycarboxylic acids or derivatives thereof, such as estersand/or anhydrides, by bringing one or more benzenepolycarboxylic acidsor one or more derivatives thereof into contact with ahydrogen-containing gas in the presence of a catalyst containingmacropores.

Furthermore, the present invention also relates to selected products asobtained by the hydrogenation according to the invention as such, i.e.the corresponding cyclohexane compounds, in particular ofcyclohexanedicarboxylic esters and cyclohexanetricarboxylic esters, inparticular the cyclohexanedicarboxylic esters andcyclohexanetricarboxylic esters. Furthermore, the invention also relatesto the use of the obtained cyclohexanedicarboxylic esters asplasticizers in plastics.

In U.S. Pat. No. 5,286,898 and U.S. Pat. No. 5,319,129, dimethylterephthalate is hydrogenated at ≧140° C. and a pressure of from 50 to170 bar over supported Pd catalysts which are treated with Ni, Pt and/orRu to give the corresponding dimethyl hexahydroterephthalate. In DE-A 2823 165, aromatic carboxylic esters are hydrogenated at from 70 to 250°C. and from 30 to 200 bar over supported Ni, Ru, Rh and/or Pd catalyststo give the corresponding cycloaliphatic carboxylic esters. U.S. Pat.No. 3,027,398 describes the hydrogenation of dimethyl terephthalate oversupported Ru catalysts at from 110 to 140° C. and from 35 to 105 bar.

EP-A 0 603 825 relates to a process for the preparation of1,4-cycylohexanedicarboxylic acid by hydrogenating terephthalic acid byusing a supported palladium catalyst, wherein as support alumina, silicaor active charcoal is used. The process described therein isparticularly characterized in that the solution comprising an1,4-cyclohexanedicarboxylic acid as obtained in a first step is broughtinto contact with steam, thereby leading to an extraction of theimpurities as obtained in said solution. This process is, however, onlyapplicable to acids, since when using it for derivatives, such as e.g.esters, anhydrides, etc. there exists the risk of hydrolysis. The use ofa support comprising macropores is not mentioned in this application.

Up to now, predominantly phthalic acid esters, such as dibutyl, dioctylor isononyl esters of phthalic acid have been used as plasticizers inplastics, such as PVC, as may be deduced from e.g. FR-A 2,397,131.However, since recently these compounds are regarded as beingdetrimental under health aspects and thus their use in plastics forproducing e.g. tools for children is under an increasing criticism, insome countries their use is even forbidden.

The use of several cyclohexane-1,2-dicarboxylic acid esters asplasticizer is known from the prior art. Described is the use ofcyclohexanedicarboxylic acid dimethyl or diethyl esters (DE-A 28 23165), cyclohexane-1,2-dicarboxylic acid di(isononyl)ester (EP-A07-011074) and cyclohexane-1,2-dicarboxylic acid di(2-ethylhexyl)ester(DE-A 12 63 296) as plasticizers in plastic.

It is an object of the present invention to provide a process forhydrogenating benzenepolycarboxylic acids or derivatives, in particularbenzenedicarboxylic esters, using specific catalysts, by means of whichthe corresponding ring-hydrogenated derivatives, in particularcyclohexanedicarboxylic esters, can be obtained with a very highselectivity and in a very high space-time yield without significantsecondary reactions.

A further object of the present invention lies in providing new productswhich are obtainable by the hydrogenation of benzenepolycarboxylic acid(derivatives) according to the invention, which should be preferablyuseable as plasticizers in plastics.

The present invention accordingly provides a process for hydrogenating abenzenepolycarboxylic acid or a derivative thereof or a mixture of twoor more thereof by bringing the benzenepolycarboxylic acid or thederivative thereof or the mixture of two or more thereof into contactwith a hydrogen-containing gas in the presence of a catalyst whichcomprises as active metal at least one metal of transition group VIII ofthe Periodic Table alone or together with at least one metal oftransition group I or VIII of the periodic table applied to a supportwhich contains macropores with the proviso that

if dimethyl terephthalate is hydrogenated, the hydrogenation using acatalyst which comprises as active metal ruthenium either alone ortogether with at least one metal of transition group I, VII or VIII ofthe Periodic Table applied to a support, where the support has a meanpore diameter of at least 50 nm and a BET surface area of at most 30m²/g and the amount of the active metal is from 0.01 to 30% by weight,based on the total weight of the catalyst, and the ratio of the surfaceareas of the active metal and the catalyst support is less than 0.05, or

a catalyst which comprises as active metal ruthenium either alone ortogether with at least one metal of transition group I, VII or VIII ofthe Periodic Table in an amount of from 0.01 to 30% by weight, based onthe total weight of the catalyst, applied to a support, where from 10 to50% of the pore volume of the support is formed by macropores having apore diameter in the range from 50 nm to 10,000 nm and from 50 to 90% ofthe pore volume of the support is formed by mesopores having a porediameter in the range from 2 to 50 nm, where the sum of the pore volumesadds up to 100%, is excluded.

In a preferred embodiment, the present invention provides a process forhydrogenating a benzenepolycarboxylic acid or a derivative thereof or amixture of two or more thereof, wherein the catalyst comprises as activemetal at least one metal of transition group VIII of the Periodic Tableeither alone or together with at least one metal of transition group Ior VII of the Periodic Table applied to a support, where the support hasa mean pore diameter of at least 50 nm and a BET surface area of at most30 m²/g and the amount of the active metal is from 0.01 to 30% byweight, based on the total weight of the catalyst (catalyst 1).

Furthermore, the present invention provides a process of this type inwhich the catalyst comprises as active metal at least one metal oftransition group VIII of the Periodic Table either alone or togetherwith at least one metal of transition group I or VII of the PeriodicTable in an amount of from 0.01 to 30% by weight, based on the totalweight of the catalyst, applied to a support, where from 10 to 50% ofthe pore volume of the support is formed by macropores having a porediameter in the range from 50 nm to 10,000 nm and from 50 to 90% of thepore volume of the support is formed by mesopores having a pore diameterin the range from 2 to 50 nm, where the sum of the pore volumes adds upto 100% (catalyst 2).

In a further preferred embodiment, the present invention provides aprocess as defined above in which the catalyst (catalyst 3) comprises asactive metal at least one metal of transition group VIII of the PeriodicTable either alone or together with at least one metal of transitiongroup I or VII of the Periodic Table in an amount of from 0.01 to 30% byweight, based on the total weight of the catalyst, applied to a support,where the support has a mean pore diameter of at least 0.1 {grave over(l)}m and a BET surface area of at most 15 m²/g. Supports used can inprinciple be all supports which contain macropores, i.e. supports whichcontain only macropores as well as those which contain mesopores and/ormicropores in addition to macropores.

Active metals which can be used are in principle all metals oftransition group VIII of the Periodic Table. Preference is given tousing platinum, rhodium, palladium, cobalt, nickel or ruthenium or amixture of two or more thereof as active metal; particular preference isgiven to using ruthenium as active metal. Among the metals of transitiongroup I or VII or else transition groups I and VII of the Periodic Tablewhich are likewise all usable in principle, preference is given to usingcopper and/or rhenium.

For the purposes of the present invention, the terms “macropores” and“mesopores” are used as they are defined in Pure Appl. Chem., 45 (1976),79, namely as pores whose diameter is above 50 nm (macropores) or whosediameter is from 2 nm and 50 nm (mesopores).

The active metal content is generally from about 0.01 to about 30% byweight, preferably from about 0.01 to about 5% by weight and inparticular from about 0.1 to about 5% by weight, in each case based onthe total weight of the catalyst used; the contents preferably used inthe preferred catalysts 1 to 3 described below will again be specifiedindividually in the discussion of these catalysts.

The term “benzenepolycarboxylic acid or a derivative thereof” used forthe purposes of the present invention encompasses allbenzenepolycarboxylic acids as such, e.g. phthalic acid, isophthalicacid, terephthalic acid, trimellitic acid, trimesic acid, hemimelliticacid and pyromellitic acid, and derivatives thereof, particularlymonoesters, diesters and possibly triesters and tetra-esters, inparticular alkyl esters, and anhydrides. The compounds which arepreferably used will be briefly described once more in the section“Method of carrying out the process” below.

The catalysts 1 to 3 which are preferably used will now be described indetail below. In the description, ruthenium is used as active metal byway of example, but the statements made below are also applicable to theother active metals which can be used, as defined herein.

Catalyst 1

The catalysts 1 used according to the present invention can be producedindustrially by applying at least one metal of transition group VIII ofthe Periodic Table and, if desired, at least one metal of transitiongroup I or VII of the Periodic Table to a suitable support.

The metal(s) can be applied by steeping the support in aqueous metalsalt solutions such as aqueous ruthenium salt solutions, by sprayingappropriate metal salt solutions onto the support or by other suitablemethods. Suitable metal salts of transition group I, VII or VIII of thePeriodic Table are the nitrates, nitrosyl nitrates, halides, carbonates,carboxylates, acetylacetonates, chloro complexes, nitrito complexes orammine complexes of the corresponding metals, with preference beinggiven to the nitrates and nitrosyl nitrates.

In the case of metals which have not only a metal of transition groupVIII of the Periodic Table but also further metals applied as activemetals to the support, the metal salts or metal salt solutions can beapplied simultaneously or in succession.

The supports which have been coated or impregnated with the metal saltsolution are subsequently dried, preferably at from 100 to 150° C., and,if desired, calcined at from 200 to 600° C., preferably from 350 to 450°C. In the case of separate impregnation, the catalyst is dried and, ifdesired, calcined as described above after each impregnation step. Theorder in which the support is impregnated with the active components isimmaterial.

The coated and dried and, if desired, calcined supports are subsequentlyactivated by treatment in a gas stream comprising free hydrogen at fromabout 30 to about 600° C., preferably from about 150 to about 450° C.The gas stream preferably consists of from 50 to 100% by volume of H₂and from 0 to 50% by volume of N₂.

The metal salt solution or solutions are applied to the support orsupports in such an amount that the total active metal content, in eachcase based on the total weight of the catalyst, is from about 0.01 toabout 30% by weight, preferably from about 0.01 to about 5% by weight,more preferably from about 0.01 to about 1% by weight and in particularfrom about 0.05 to about 1% by weight.

The total metal surface area on the catalyst 1 is preferably from about0.01 to about 10 m²/g, more preferably from about 0.05 to about 5 m²/gand in particular from about 0.05 to about 3 m²/g of the catalyst. Themetal surface area is determined by means of the chemisorption methoddescribed by J. Lemaitre et al. in “Characterization of HeterogenousCatalysts”, edited by Francis Delanney, Marcel Dekker, New York 1984,pp. 310-324.

In the catalyst 1 used according to the present invention, the ratio ofthe surface areas of the active metal/metals and the catalyst support ispreferably less than about 0.05, with the lower limit being about0.0005.

The support materials which can be used for producing the catalysts usedaccording to the present invention are those which are macroporous andhave a mean pore diameter of at least about 50 nm, preferably at leastabout 100 nm, in particular at least about 500 nm, and whose BET surfacearea is at most about 30 m²/g, preferably at most about 15 m²/g, morepreferably at most about 10 m²/g, in particular at most about 5 m²/g andmore preferably at most about 3 m²/g. The mean pore diameter of thesupport is preferably from about 100 nm to about 200 {grave over (l)}m,more preferably from about 500 nm to about 50 {grave over (l)}m. Thesurface area of the support is preferably from about 0.2 to about 15m²/g, more preferably from about 0.5 to about 10 m²/g, in particularfrom about 0.5 to about 5 m²/g and more preferably from about 0.5 toabout 3 m²/g.

The surface area of the support is determined by the BET method using N₂adsorption, in particular in accordance with DIN 66131. The mean porediameter and the pore size distribution are determined by Hgporosimetry, in particular in accordance with DIN 66133.

The pore size distribution of the support is preferably approximatelybimodal, with the pore diameter distribution having maxima at about 600nm and about 20 {grave over (l)}m in the bimodal distributionrepresenting a specific embodiment of the invention.

Further preference is given to a support which has a surface area of1.75 m²/g and this bimodal distribution of the pore diameter. The porevolume of this preferred support is preferably about 0.53 ml/g.

Macroporous support materials which can be used are, for example,macropores containing activated carbon, silicon carbide, aluminum oxide,silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide,zinc oxide or mixtures of two or more thereof, with preference beinggiven to using aluminum oxide and zirconium dioxide.

Further details regarding catalyst 1 or its production may be found inDE-A 196 24 484.6, whose entire contents on this subject areincorporated by reference into the present application.

Catalyst 2

The catalysts 2 used according to the present invention comprise one ormore metals of transition group VIII of the Periodic Table as activecomponent(s) on a support as defined herein. Preference is given tousing ruthenium, palladium and/or rhodium as active component(s).

The catalysts 2 used according to the present invention can be producedindustrially by application of an active metal of transition group VIIIof the Periodic Table, preferably ruthenium or palladium, and, ifdesired, at least one metal of transition group I or VII of the PeriodicTable to a suitable support. The application can be achieved by steepingthe support in aqueous metal salt solutions, for example ruthenium orpalladium salt solutions, by spraying appropriate metal salt solutionsonto the support or by other suitable methods. Suitable metal salts forpreparing the metal salt solutions are the nitrates, nitrosyl nitrates,halides, carbonates, carboxylates, acetylacetonates, chloro complexes,nitrito complexes or ammine complexes of the corresponding metals, withpreference being given to the nitrates and nitrosyl nitrates.

In the case of catalysts which have a plurality of active metals appliedto the support, the metal salts or metal salt solutions can be appliedsimultaneously or in succession.

The supports which have been coated or impregnated with the metal saltsolution are subsequently dried, preferably at from 100 to 150° C. Ifdesired, these supports can be calcined at from 200 to 600° C.,preferably from 350 to 450° C. The coated supports are subsequentlyactivated by treatment in a gas stream comprising free hydrogen at from30 to 600° C., preferably from 100 to 450° C., and in particular from100 to 300° C. The gas stream preferably consists of from 50 to 100% byvolume of H₂ and from 0 to 50% by volume of N₂.

If a plurality of active metals are applied to the support and theapplication is carried out in succession, the support can be dried atfrom 100 to 150° C. and, if desired, calcined at from 200 to 600° C.after each application or impregnation. The order in which the metalsalt solution is applied to the support or the support is impregnatedwith the metal salt solution is immaterial.

The metal salt solution is applied to the support(s) in such an amountthat the active metal content is from 0.01 to 30% by weight, preferablyfrom 0.01 to 10% by weight, more preferably from 0.01 to 5% by weight,and in particular from 0.3 to 1% by weight, based on the total weight ofthe catalyst.

The total metal surface area on the catalyst is preferably from 0.01 to10 m²/g, particularly preferably from 0.05 to 5 m²/g and more preferablyfrom 0.05 to 3 m²/g of the catalyst. The metal surface area is measuredby the chemisorption method as described in J. Lemaitre et al.,“Characterization of Heterogenous Catalysts”, edited by FrancisDelanney, Marcel Dekker, New York (1984), pp. 310-324.

In the catalyst 2 used according to the present invention, the ratio ofthe surface areas of the active metal or metals and the catalyst supportis less than about 0.3, preferably less than about 0.1 and in particularabout 0.05 or less, with the lower limit being about 0.0005.

The support materials which can be used for producing the catalysts 2used according to the present invention possess macropores andmesopores.

The supports which can be used according to the present invention have apore distribution in which from about 5 to about 50%, preferably fromabout 10 to about 45%, more preferably from about 10 to about 30 and inparticular from about 15 to about 25%, of the pore volume is formed bymacropores having pore diameters in the range from about 50 nm to about10,000 nm and from about 50 to about 95%, preferably from about 55 toabout 90%, more preferably from about 70 to about 90% and in particularfrom about 75 to about 85%, of the pore volume is formed by mesoporeshaving a pore diameter of from about 2 to about 50 nm where in each casethe sum of the pore volumes adds up to 100%.

The total pore volume of the supports used according to the presentinvention is from about 0.05 to 1.5 cm³/g, preferably from 0.1 to 1.2cm³/g and in particular from about 0.3 to 1.0 cm³/g. The mean porediameter of the supports used according to the present invention is fromabout 5 to 20 nm, preferably from about 8 to about 15 nm and inparticular from about 9 to about 12 nm.

The surface area of the support is preferably from about 50 to about 500m²/g, more preferably from about 200 to about 350 m²/g and in particularfrom about 250 to about 300 m²/g of the support.

The surface area of the support is determined by the BET method using N₂adsorption, in particular in accordance with DIN 66131. The mean porediameter and the size distribution are determined by Hg porosimetry, inparticular in accordance with DIN 66133.

Although all support materials known in catalyst production, i.e. thosewhich have the above-defined pore size distribution, can be used inprinciple, preference is given to using macropores containing activatedcarbon, silicon carbide, aluminum oxide, silicon dioxide, titaniumdioxide, zirconium dioxide, magnesium oxide, zinc oxide or mixturesthereof, more preferably aluminum oxide and zirconium dioxide.

Further details regarding catalyst 2 or its production may be found inDE-A 196 24 485.4, whose entire contents on this subject areincorporated by reference into the present application.

Catalyst 3

The catalysts 3 used according to the present invention can be producedindustrially by application of an active metal of transition group VIIIof the Periodic Table and, if desired, at least one metal of transitiongroup I or VII of the Periodic Table to a suitable support. Theapplication can be achieved by steeping the support in aqueous metalsalt solutions such as ruthenium salt solutions, by spraying appropriatemetal salt solutions onto the support or by other suitable methods.Salts which are suitable as ruthenium salts for preparing the rutheniumsalt solutions and as metal salts of transition group I, VII or VIII arethe nitrates, nitrosyl nitrates, halides, carbonates, carboxylates,acetylacetonates, chloro complexes, nitrito complexes or amminecomplexes of the corresponding metals; preference is given to thenitrates and nitrosyl nitrates.

In the case of catalysts which comprise a plurality of metals applied tothe support, the metal salts or metal salt solutions can be appliedsimultaneously or in succession.

The supports coated or impregnated with the ruthenium salt or metal saltsolution are then dried, preferably at from 100 to 150° C., and, ifdesired calcined at from 200 to 600° C.

The coated supports are subsequently activated by treating the coatedsupports in a gas stream comprising free hydrogen at from 30 to 600° C.,preferably from 150 to 450° C. The gas stream preferably consists offrom 50 to 100% by volume of H₂ and from 0 to 50% by volume of N₂.

If both the active metal of transition group VIII of the Periodic Tableand metals of transition group I or VII are applied to the support andthe application is carried out in succession, the support can be driedat from 100 to 150° C. and, if desired, calcined at from 200 to 600° C.after each application or impregnation. The order in which the metalsalt solutions are applied or the support is impregnated with them isimmaterial.

The metal salt solution is applied to the support(s) in such an amountthat from 0.01 to 30% by weight, based on the total weight of thecatalyst, of active metal are present on the support. This amount ispreferably from 0.2 to 15% by weight, particularly preferably about 0.5%by weight.

The total metal surface area on the catalyst 3 is preferably from 0.01to 10 m²/g, particularly preferably from 0.05 to 5 m²/g, in particularfrom 0.05 to 3 m² per g of the catalyst.

The support materials which can be used for producing the catalysts 3used according to the present invention are preferably ones which aremacroporous and have a mean pore diameter of at least 0.1 {grave over(l)}m, preferably at least 0.5 {grave over (l)}m, and a surface area ofat most 15 m²/g, preferably at most 10 m²/g, particularly preferably atmost 5 m²/g, in particular at most 3 m²/g. The mean pore diameter of thesupport is preferably in a range from 0.1 to 200 {grave over (l)}m, inparticular from 0.5 to 50 {grave over (l)}m. The surface area of thesupport is preferably from 0.2 to 15 m²/g, particularly preferably from0.5 to 10 m²/g, in particular from 0.5 to 5 m²/g, especially from 0.5 to3 m²/g of the support.

The surface area of the support is determined by the BET method using N₂adsorption, in particular in accordance with DIN 66131. The mean porediameter and the pore size distribution are determined by Hgporosimetry, in particular in accordance with DIN 66133. The pore sizedistribution of the support is preferably approximately bimodal, withthe pore diameter distribution having maxima at about 0.6 {grave over(l)}m and about 20 {grave over (l)}m in the bimodal distributionrepresenting a specific embodiment of the invention.

Particular preference is given to a support having a surface area ofabout 1.75 m²/g and having this bimodal distribution of the porediameter. The pore volume of this preferred support is preferably about0.53 ml/g.

Macroporous support materials which can be used are, for example,macropores containing activated carbon, silicon carbide, aluminum oxide,silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide,zinc oxide or mixtures thereof. Preference is given to aluminum oxideand zirconium dioxide.

Further details regarding catalyst 3 or its production may be found inDE-A 196 04 791.9, whose entire contents on this subject areincorporated by reference into the present application.

Method of Carrying Out the Process

In the process of the present invention, the hydrogenation is generallycarried out at from about 50 to 250° C., preferably from about 70 to220° C. The pressures used here are generally above 10 bar, preferablyfrom about 20 to about 300 bar.

The process of the present invention can be carried out eithercontinuously or batchwise, with preference being given to carrying outthe process continuously.

When the process is carried out continuously, the amount of thebenzenepolycarboxylic acid or ester to be hydrogenated or of the mixtureof two or more thereof is preferably from about 0.05 to about 3 kg perliter of catalyst per hour, more preferably from about 0.1 to about 1 kgper liter of catalyst per hour.

As hydrogenation gases, it is possible to use any gases which comprisefree hydrogen and do not contain harmful amounts of catalyst poisonssuch as CO. For example, waste gases from a reformer can be used.Preference is given to using pure hydrogen as hydrogenation gas.

The hydrogenation of the present invention can be carried out in thepresence or absence of a solvent or diluent, i.e. it is not necessary tocarry out the hydrogenation in solution.

However, preference is given to using a solvent or diluent. Solvents ordiluents which can be used are any suitable solvent or diluent. Thechoice is not critical as long as the solvent or diluent used is able toform a homogeneous solution with the benzenepolycarboxylic acid or esterto be hydrogenated. For example, the solvents or diluents can alsocomprise water.

Examples of suitable solvents or diluents include the following:

straight-chain or cyclic ethers such as tetrahydrofuran or dioxane, andalso aliphatic alcohols in which the alkyl radical preferably has from 1to 10 carbon atoms, in particular from 3 to 6 carbon atoms.

Examples of alcohols which are preferably used are i-propanol,n-butanol, i-butanol and n-hexanol.

Mixtures of these or other solvents or diluents can likewise be used.

The amount of solvent or diluent used is not restricted in anyparticular way and can be selected freely depending on requirements.However, preference is given to amounts which lead to a 10-70% strengthby weight solution of the benzenepolycarboxylic acid or ester to behydrogenated.

In the process of the present invention, particular preference is givento using the product formed in the hydrogenation, i.e. the correspondingcyclohexane derivative, as solvent, if desired in addition to othersolvents or diluents. In any case, part of the product formed in theprocess can be mixed with the benzenepolycarboxylic acid still to behydrogenated or the derivative thereof The amount of reaction productwhich is mixed in as solution or diluent is preferably from 1 to 30times, particularly preferably from 5 to 20 times, in particular from 5to 10 times, the weight of the compound to be hydrogenated.

As mentioned above, the term “benzenepolycarboxylic acids or derivativesthereof” used for the purposes of the present invention encompasses boththe respective benzenepolycarboxylic acids as such and derivativesthereof, particularly monoesters, diesters or possibly triesters ortetraesters and also anhydrides of the benzenepolycarboxylic acids. Theesters used are alkyl, cycloalkyl and alkoxyalkyl esters, where thealkyl, cycloalkyl and alkoxyalkyl groups generally have from 1 to 30,preferably from 2 to 20 and particularly preferably from 3 to 18, carbonatoms and can be branched or linear.

Specific examples are:

alkyl terephthalates such as monomethyl terephthalate, dimethylterephthalate, diethyl terephthalate, di-n-propyl terephthalate,di-n-butyl terephthalate, di-tert-butyl terephthalate, diisobutylterephthalate, monoglycol esters of terephthalic acid, diglycol estersof terephthalic acid, di-n-octyl terephthalate, diisooctylterephthalate, mono-2-ethylhexyl terephthalate, di-2-ethylhexylterephthalate, di-n-nonyl terephthalate, diisononyl terephthalate,di-n-decyl terephthalate, di-n-undecyl terephthalate, diisodecylterephthalate, diisododecyl terephthalate, di-n-octadecyl terephthalate,diisooctadecyl terephthalate, di-n-eicosyl terephthalate, monocyclohexylterephthalate, dicyclohexyl terephthalate;

alkyl phthalates such as monomethyl phthalate, dimethyl phthalate,diethyl phthalate, di-n-propyl phthalate, di-n-butyl phthalate,di-tert-butyl phthalate, diisobutyl phthalate, monoglycol esters ofphthalic acid, diglycol esters of phthalic acid, di-n-octyl phthalate,diisooctyl phthalate, di-2-ethylhexyl phthalate, di-n-nonyl phthalate,diisononyl phthalate, di-n-decyl phthalate, diisodecyl phthalate,di-n-undecyl phthalate, diisododecyl phthalate, di-n-octadecylphthalate, diisooctadecyl phthalate, di-n-eicosyl phthalate,monocyclohexyl phthalate, dicyclohexyl phthalate;

alkyl isophthalates such as monomethyl isophthalate, dimethylisophthalate, diethyl isophthalate, di-n-propyl isophthalate, di-n-butylisophthalate, di-tert-butyl isophthalate, diisobutyl isophthalate,monoglycol esters of isophthalic acid, diglycol esters of isophthalicacid, di-n-octyl isophthalate, diisooctyl isophthalate, di-2-ethylhexylisophthalate, di-n-nonyl isophthalate, diisononyl isophthalate,di-n-decyl isophthalate, diisodecyl isophthalate, di-n-undecylisophthalate, diisododecyl isophthalate, di-n-octadecyl isophthalate,diisooctadecyl isophthalate, di-n-eicosyl isophthalate, monocyclohexylisophthalate, dicyclohexyl isophthalate;

Alkyl trimellitates such as monomethyl trimellitate, dimethyltrimellitate, diethyl trimellitate, di-n-propyl trimellitate, di-n-butyltrimellitate, di-tert-butyl trimellitate, diisobutyl trimellitate, themonoglycol ester of trimellitic acid, diglycol esters of trimelliticacid, di-n-octyl trimellitate, diisooctyl trimellitate, di-2-ethylhexyltrimellitate, di-n-nonyl trimellitate, diisononyl trimellitate,di-n-decyl trimellitate, diisodecyl trimellitate, di-n-undecyltrimellitate, diisododecyl trimellitate, di-n-octadecyl trimellitate,diisooctadecyl trimellitate, di-n-eicosyl trimellitate, monocyclohexyltrimellitate, dicyclohexyl trimellitate and trimethyl trimellitate,triethyl trimellitate, tri-n-propyl trimellitate, tri-n-butyltrimellitate, tri-tert-butyl trimellitate, triisobutyl trimellitate,triglycol esters of trimellitic acid, tri-n-octyl trimellitate,triisooctyl trimellitate, tri-2-ethylhexyl trimellitate, tri-n-nonyltrimellitate, triisododecyl trimellitate, tri-n-undecyl trimellitate,triisododecyl trimellitate, tri-n-octadecyl trimellitate,triisooctadecyl trimellitate, tri-n-eicosyl trimellitate, tricyclohexyltrimellitate;

alkyl trimesates such as monomethyl trimesate, dimethyl trimesate,diethyl trimesate, di-n-propyl trimesate, di-n-butyl trimesate,di-tert-butyl trimesate, diisobutyl trimesate, monoglycol esters oftrimesic acid, diglycol esters of trimesic acid, di-n-octyl trimesate,diisooctyl trimesate, di-2-ethylhexyl trimesate, di-n-nonyl trimesate,diisononyl trimesate, di-n-decyl trimesate, diisodecyl trimesate,di-n-undecyl trimesate, diisododecyl trimesate, di-n-octadecyltrimesate, diisooctadecyl trimesate, di-n-eicosyl trimesate,monocyclohexyl trimesate, dicyclohexyl trimesate, and also trimethyltrimesate, triethyl trimesate, tri-n-propyl trimesate, tri-n-butyltrimesate, tri-tert-butyl trimesate, triisobutyl trimesate, triglycolesters of trimesic acid, tri-n-octyl trimesate, triisooctyl trimesate,tri-2-ethyl-hexyl trimesate, tri-n-nonyl trimesate, triisododecyltrimesate, tri-n-undecyl trimesate, triisododecyl trimesate,tri-n-octadecyl trimesate, triisooctadecyl trimesate, tri-n-eicosyltrimesate, tricyclohexyl trimesate;

alkyl hemimellitates such as monomethyl hemimellitate, dimethylhemimellitate, diethyl hemimellitate, di-n-propyl hemimellitate,di-n-butyl hemimellitate, di-tert-butyl hemimellitate, diisobutylhemimellitate, monoglycol esters of hemimellitic acid, diglycol estersof hemimellitic acid, di-n-octyl hemimellitate, diisooctylhemimellitate, di-2-ethylhexyl hemimellitate, di-n-nonyl hemimellitate,diisononyl hemimellitate, di-n-decyl hemimellitate, diisodecylhemimellitate, di-n-undecyl hemimellitate, diisododecyl hemimellitate,di-n-octadecyl hemimellitate, diisooctadecyl hemimellitate, di-n-eicosylhemimellitate, monocyclohexyl hemimellitate, dicyclohexyl hemimellitate,and also trimethyl hemimellitate, triethyl hemimellitate, tri-n-propylhemimellitate, tri-n-butyl hemimellitate, tri-tert-butyl hemimellitate,triisobutyl hemimellitate, triglycol esters of hemimellitic acid,tri-n-octyl hemimellitate, triisooctyl hemimellitate, tri-2-ethylhexylhemimellitate, tri-n-nonyl hemimellitate, triisododecyl hemimellitate,tri-n-undecyl hemimellitate, triisododecyl hemimellitate,tri-n-octadecyl hemimellitate, triisooctadecyl hemimellitate,tri-n-eicosyl hemimellitate, tricyclohexyl hemimellitate;

alkyl pyromellitates such as monomethyl pyromellitate, dimethylpyromellitate, diethyl pyromellitate, di-n-propyl pyromellitate,di-n-butyl pyromellitate, di-tert-butyl pyromellitate, diisobutylpyromellitate, monoglycol esters of pyromellitic acid, diglycol estersof pyromellitic acid, di-n-octyl pyromellitate, diisooctylpyromellitate, di-2-ethylhexyl pyromellitate, di-n-nonyl pyromellitate,diisononyl pyromellitate, di-n-decyl pyromellitate, diisodecylpyromellitate, di-n-undecyl pyromellitate, diisododecyl pyromellitate,di-n-octadecyl pyromellitate, diisooctadecyl pyromellitate, di-n-eicosylpyromellitate, monocyclohexyl pyromellitate, trimethyl pyromellitate,triethyl pyromellitate, tri-n-propyl pyromellitate, tri-n-butylpyromellitate, tri-tert-butyl pyromellitate, triisobutyl pyromellitate,triglycol esters of pyromellitic acid, tri-n-octyl pyromellitate,triisooctyl pyromellitate, tri-2-ethylhexyl pyromellitate, tri-n-nonylpyromellitate, triisododecyl pyromellitate, tri-n-undecyl pyromellitate,triisododecyl pyromellitate, tri-n-octadecyl pyromellitate,triisooctadecyl pyromellitate, tri-n-eicosyl pyromellitate,tricyclohexyl pyromellitate, and also tetramethyl pyromellitate,tetraethyl pyromellitate, tetra-n-propyl pyromellitate, tetra-n-butylpyromellitate, tetra-tert-butyl pyromellitate, tetraisobutylpyromellitate, tetraglycol esters of pyromellitic acid, tetra-n-octylpyromellitate, tetraisooctyl pyromellitate, tetra-2-ethylhexylpyromellitate, tetra-n-nonyl pyromellitate, tetraisododecylpyromellitate, tetra-n-undecyl pyromellitate, tetraisododecylpyromellitate, tetra-n-octadecyl pyromellitate, tetraisooctadecylpyromellitate, tetra-n-eicosyl pyromellitate, tetracyclohexylpyromellitate;

anhydrides of phthalic acid, trimellitic acid, hemimellitic acid andpyromellitic acid.

Of course, it is also possible to use mixtures of two or more of thesecompounds.

The products as obtained according to the invention are thecorresponding cyclohexanepolycarboxylic acids orcyclohexanepoycarboxylic acid derivatives.

Furthermore, the present invention relates to the following newcyclohexanepolycarboxylic acids or cyclohexanpolycarboxylic acidderivatives as such:

cyclohexane-1,2-dicarboxylic acid di(isopentyl) ester, obtainable byhydrogenation of a di(isopentyl)phthalate having the Chemical Abstractsregistry number (in the following: CAS No.) 84777-06-0;

cyclohexane-1,2-dicarboxylic acid di(isoheptyl) ester, obtainable byhydrogenating the di(isoheptyl)phthalate having the CAS No. 71888-89-6;

cyclohexane-1,2-dicarboxylic acid di(isononyl) ester, obtainable byhydrogenating the di(isononyl)phthalate having the CAS No. 68515-48-0;

cyclohexane-1,2-dicarboxylic acid di(isononyl) ester, obtainable byhydrogenating the di(isononyl)phthalate having the CAS No. 28553-12-0,which is based on n-butene;

cyclohexane-1,2-dicarboxylic acid di(isononyl) ester, obtainable byhydrogenating the di(isononyl)phthalate having the CAS No. 28553-12-0,which is based on isobutene;

a 1,2-di-C₉-ester of cyclohexanedicarboxylic acid, obtainable byhydrogenating the di(nonyl)phthalate having the CAS No. 68515-46-8;

cyclohexane-1,2-dicarboxylic acid di(isodecyl) ester, obtainable byhydrogenating a di(isodecyl)phthalate having the CAS No. 68515-49-1;

1,2-C₇₋₁₁-ester of cyclohexanedicarboxylic acid, obtainable byhydrogenating the corresponding phthalic acid ester having the CAS No.68515-42-4;

1,2-di-C₇₋₁₁-ester of cyclohexanedicarboxylic acid, obtainable byhydrogenating the di-C₇₋₁₁-phthalates having the following CAS Nos.:

111381-89-6,

111381-90-9,

111381-91-0,

68515-44-6,

68515-45-7 and

3648-20-7;

a 1,2-di-C₉₋₁₁-ester of cyclohexanedicarboxylic acid, obtainable byhydrogenating a di-C₉₋₁₁-phthalate having the CAS No. 98515-43-5;

a 1,2-di(isodecyl)cyclohexanedicarboxylic acid ester, obtainable byhydrogenating a di(isodecyl)phthalate, consisting essentially ofdi-(2-propylheptyl)phthalate;

1,2-di-C₇₋₉-cyclohexanedicarboxylic acid ester, obtainable byhydrogenating the corresponding phthalic acid ester, which comprisesbranched and linear C₇₋₉-alkylester groups; respective phthalic acidesters which may be e.g. used as starting materials have the followingCAS Nos.:

di-C₇₋₉-alkylphthalate having the CAS No. 111 381-89-6;

di-C₇-alkylphthalate having the CAS No. 68515-44-6; and

di-C₉-alkylphthalate having the CAS No. 68515-45-7.

Furthermore, the present invention also provides for the use ofcyclohexanepolycarboxylic esters, in particular thecyclohexanepolycarboxylic esters obtained using the process of thepresent invention, as plasticizers in plastics. Here, preference isgenerally given to diesters and triesters containing alkyl groups havingfrom 3 to 18 carbon atoms and particular preference is given to theabovementioned, individually listed esters having from 3 to 18 carbonatoms.

More preferably, the above explicitly mentioned new C₅, C₇-, C₉-, C₁₀-,C₇₋₁₁-, C₉₋₁₁- and C₇₋₉-esters of 1,2-cyclohexanedicarboxylic acids, asbeing obtainable by hydrogenating the corresponding phthalates and morepreferably the hydrogenation products of the commercially availablebenzenepolycarboxylic acid esters with the trade names Jayflex DINP (CASNo. 68515-48-0), Jayflex DIDP (CAS No. 68515-49-1), Palatinol 9-P,Vestinol 9 (CAS No. 28553-12-0), TOTM-I (CAS No. 3319-31-1), Linplast68-TM and Palatinol N (CAS No. 28553-12-0) are used as plasticizers inplastics. Among those is in tun preferred to use these compounds ormixtures thereof as plasticizers in mass plastics, such as e.g. PVC andpolyolefins, such as polyethylene, polypropylene, polyisoprene andcopolymers of ethylene or propylene and 1-butene, 1-hexene and 1-octene.

Compared to the until now predominantly phthalates as used asplasticizers, the cyclohexanepolycarboxylic acid (derivatives), as usedaccording to the invention, exhibit a lower density and viscosity andlead to e.g. an improvement of the flexibility at low temperatures(Kälteflexibilität) of the plastic when compared with the usage of thecorresponding phthalates as plasticizers, while properties such as shoreA hardness and the mechanical properties of the resulting plastics areidentical to those as resulting from the usage of phthalates.Furthermore, the cyclohexanepolycarboxylic acid (derivative)s accordingto the invention exhibit an improved process ability in the dry blendand as a result thereof a higher production speed. In the Plastisolprocessing by exhibit advantages attributed to the lower viscosity whencompared with conventional phthalates.

The process of the present invention is illustrated below by means ofsome examples.

EXAMPLES Examples of Catalyst Production

A mesoporous/macroporous aluminum oxide support which was in the form of4 mm extrudates and had a BET surface area of 238 m²/g and a pore volumeof 0.45 ml/g was impregnated with an aqueous ruthenium(III) nitratesolution having a concentration of 0.8% by weight. 0.15 ml/g (about 33%of the total volume) of the pores of the support had a diameter in therange from 50 nm to 10,000 nm and 0.30 ml/g (about 67% of the total porevolume) of the pores of the support had a pore diameter in the rangefrom 2 to 50 nm. The volume of solution taken up by the support duringimpregnation corresponded approximately to the pore volume of thesupport used.

The support which had been impregnated with the ruthenium(III) nitratesolution was subsequently dried at 120° C. and activated (reduced) at200° C. in a stream of hydrogen. The catalyst produced in this waycontained 0.05% by weight of ruthenium, based on the weight of thecatalyst.

Example 1

In a 300 ml pressure reactor, 10 g of the Ru catalyst as described inthe example of catalyst production were placed in a catalyst basketinsert and 197 g (0.5 mol) of diisooctyl phthalate were added. Thehydrogenation was carried out using pure hydrogen at 80° C. and aconstant pressure of 200 bar. Hydrogenation was continued until no morehydrogen was taken up (4 h). The reactor was subsequently vented. Theconversion of the diisooctyl phthalate was 100%. The yield of diisooctylhexahydrophthalate was 99.7%, based on the total amount of diisooctylphthalate used.

Example 2

In a 300 ml pressure reactor, 10 g of the Ru catalyst were placed in acatalyst basket insert and 194 g (0.46 mol) of diisononyl phthalate wereadded. The hydrogenation was carried out using pure hydrogen at 80° C.and a constant pressure of 100 bar. Hydrogenation was continued until nomore hydrogen was taken up (10 h). The reactor was subsequently vented.The conversion of diisononyl phthalate was 100%. The yield of diisononylhexahydrophthalate was 99.5%, based on the total amount of diisononylphthalate used.

Example 3

In a 300 ml pressure reactor, 10 g of the Ru catalyst as described inthe example of catalyst production were placed in a catalyst basketinsert and 195 g (0.39 mol) of diisododecyl phthalate were added. Thehydrogenation was carried out using pure hydrogen at 80° C. and aconstant pressure of 200 bar. Hydrogenation was continued until no morehydrogen was taken up (4 h). The reactor was subsequently vented. Theconversion of diisododecyl phthalate was 100%. The yield of diisododecylhexahydrophthalate was 99.5%, based on the total amount of diisododecylphthalate used.

Example 4

In a 300 ml pressure reactor, 10 g of the Ru catalyst were placed in acatalyst basket insert and 38.4 g (0.2 mol) of dimethyl isophthalate,dissolved in 100 g of THF, were added. The hydrogenation was carried outusing pure hydrogen at 80° C. and a constant pressure of 200 bar.Hydrogenation was continued until no more hydrogen was taken up and thereactor was subsequently vented. The conversion of dimethyl isophthalatewas 95.3%. The yield of dimethyl hexahydroisophthalate was 95.3%.

Example 5

In a 300 ml pressure reactor, 10 g of the Ru catalyst were placed in acatalyst basket insert and 25.2 g (0.1 mol) of trimethyl trimesate,dissolved in 100 g of THF, were added. The hydrogenation was carried outusing pure hydrogen at 120° C. and a constant pressure of 200 bar.Hydrogenation was continued until no more hydrogen was taken up and thereactor was subsequently vented. The conversion of trimethyl trimesatewas 97%. The yield of trimethyl hexahydrotrimesate was 93%.

Example 6

In a 300 ml pressure reactor, 10 g of the Ru catalyst were placed in acatalyst basket insert and 25.2 g (0.1 mol) of trimethyl trimellitate,dissolved in 100 g of THF, were added. The hydrogenation was carried outusing pure hydrogen at 120° C. and a constant pressure of 200 bar.Hydrogenation was continued until no more hydrogen was taken up and thereactor was subsequently vented. The conversion of trimethyltrimellitate was 35%. The yield of trimethyl hexahydrotrimellitate was33%.

Example 7

In a 300 ml pressure reactor, 10 g of the Ru catalyst were placed in acatalyst basket insert and 10.0 g (0.03 mol) of tetramethylpyromellitate, dissolved in 100 g of THF, were added. The hydrogenationwas carried out using pure hydrogen at 80° C. and a constant pressure of200 bar. Hydrogenation was continued until no more hydrogen was taken upand the reactor was subsequently vented. The conversion of tetramethylpyromellitate was 45%. The yield of tetramethyl hexahydropyromellitatewas 44%.

Example 8

In a 1.2 l pressure reactor, 53 g of the supported Ru catalyst wereplaced in a catalyst basket insert and 800 g (1.9 mol) Jayflex DINP (CASNo. 68515-48-0) were added. The hydrogenation was carried out using purehydrogen at 80° C. and a constant pressure of 200 bar. Hydrogenation wascontinued until no more hydrogen was taken up (6 h) and the reactor wassubsequently vented. The conversion of Jayflex DINP was 100%. The yieldof the corresponding cyclohexanedicarboxylic acid ester was 99.5%,relative to the total amount of the added Jayflex DINP.

Example 9

In a 0.3 l pressure reactor, 10 g of the supported Ru catalyst wereplaced in a catalyst basket insert and 150 g (0.35 mol) Palatinol 9-Pwere added. The hydrogenation was carried out using pure hydrogen at atemperature of 120° C. and a constant pressure of 200 bar. Hydrogenationwas continued until no more hydrogen was taken up (2 h) and the reactorwas subsequently vented. The conversion of Palatinol 9-P (1,2-di(nonyl,linear and branched)benzenedicarboxylic acid ester) was 100%. The yieldof the corresponding cyclohexanedicarboxylic acid ester was 99.4%,relative to the total amount of the used Palatinol 9-P.

Example 10

In a 1.2 l pressure reactor, 53 g of the supported Ru catalyst wereplaced in a catalyst basket insert and 780 g (1.87 mol) Vestinol 9 (CASNo. 28553-12-0) were added. The hydrogenation was carried out using purehydrogen at a temperature of 120° C. and a constant pressure of 200 bar.Hydrogenation was continued until no more hydrogen was taken up (4 h)and the reactor was subsequently vented. The conversion of thecorresponding cyclohexanedicarboxylic acid ester was 99.4%, relative tothe total amount of the used Vestinol 9.

Example 11

In a 1.2 l pressure reactor, 53 g of the supported Ru catalyst wereplaced in a catalyst basket insert and 760 g (1.7 mol) Jayflex DIDP (CASNo. 68515-49-1) were added. The hydrogenation was carried out using purehydrogen at 80° C. and a constant pressure of 200 bar. Hydrogenation wascontinued until no more hydrogen was taken up (10 h) and the reactor wassubsequently vented. The conversion of Jayflex DIDP was 100%. The yieldof the corresponding cyclohexanedicarboxylic acid ester was 99.5%,relative to the total amount of the used Jayflex DIDP.

Example 12

In a 1.2 l pressure reactor, 53 g of the supported Ru catalyst wereplaced in a catalyst basket insert and 800 g (1.56 mol) TOTM-I(1,2,4-tri(2-ethylhexyl)benzenetricarboxylic acid ester) were added. Thehydrogenation was carried out using pure hydrogen at 100° C. and aconstant pressure of 200 bar. Hydrogenation was continued until no morehydrogen was taken up (20 h) and the reactor was subsequently vented.The conversion of TOMT-I was 95%. The yield of the correspondingcyclohexanedicarboxylic acid ester was 94%, relative to the total amountof the used TOMT-I.

Example 13

In a 300 ml pressure reactor, 10 g of the supported Ru catalyst wereplaced in a catalyst basket insert and 150 g (0.32 mol) Linplast 68-TM(1,2,4-tri(linear C₆₋₈-alkyl)benzoltricarboxylic acid ester) were added.The hydrogenation was carried out using pure hydrogen at a temperatureof 120° C. and a constant pressure of 200 bar. Hydrogenation wascontinued until no more hydrogen was taken up (11 h) and the reactor wassubsequently vented. The conversion of Linplast 68-TM was 100%. Theyield of the corresponding cyclohexanedicarboxylic acid ester was 99.2%,relative to the total amount of the used Linplast 68-TM.

Example 14

A vertical high-pressure tube made of steel having an inner diameter of30 mm and a length of 2.2 m was filled with 1.4 l of the supported Rucatalyst. In the slurry process, 0.45 kg/h Palatinol N (CAS No.28553-12-0) were pumped together with pure hydrogen from the bottom tothe top through the reactor at an average temperature of 125° C. and apressure of 200 bar. After leaving the high-pressure reactor, part ofthe reaction product was reintroduced into the reactor together with newPalatinol N, while the residual reaction product was vented in acontainer. The hydrogenation was carried out with a 20% excess of thetheoretically required hydrogen while controlling the spent gas.Gaschromatographic analysis of the reaction product showed thatPalatinol N has been reacted to an extent of 99.5%. The correspondingcyclohexanedicarboxylic acid ester was obtained with a selectivity of99.2%. In order to remove the remaining 0.5% Palatinol from the reactionproduct, the same was pumped through the reactor from the bottom to thetop in an amount of 1 kg/h, and the product was vented in a container.The addition of hydrogen was continued as described above. Subsequently,no Palatinol N was found in the product. The selectivity with respect tothe corresponding cyclohexanedicarboxylic acid ester after the secondhydrogenation was 99%. As side components, about 1% low boilingcomponents (components having a lower boiling point compared tocyclohexanedicarboxylic acid ester) were found. These components werereduced by means of a vapor distillation at 170° C. and a pressure of 50mbar. The product consisted after this work-up of 99.7%cyclohexanedicarboxylic acid ester.

We claim:
 1. A process for hydrogenating a benzenepolycarboxylic acid ora derivative thereof to the corresponding cyclohexane polycarboxylicacid or a mixture of two or more thereof by bringing thebenzenepolycarboxylic acid or the derivative thereof or the mixture oftwo or more thereof into contact with a hydrogen-containing gas in thepresence of a catalyst which comprises as active metal at least onemetal of transition group VIII of the Periodic Table alone or togetherwith at least one metal of transition group I or VII of the periodictable applied to a support which contains macropores having a porediameter of greater than 50 nm according to the definition in PureApplied Chemistry 45, p. 79 (1976) with the proviso that if dimethylterephthalate is hydrogenated, the hydrogenation using a catalyst whichcomprises as active metal ruthenium either alone or together with atleast one metal of transition group I, VII or VIII of the Periodic Tableapplied to a support, where the support has a mean pore diameter of atleast 50 nm and a BET surface area of at most 30 m²/g and the amount ofthe active metal is from 0.01 to 30% by weight, based on the totalweight of the catalyst, and the ratio of the surface areas of the activemetal and the catalyst support is less than 0.05, and/or a catalystwhich comprises as active metal ruthenium either alone or together withat least one metal of transition group I, VII or VIII of the PeriodicTable in an amount of from 0.01 to 30% by weight, based on the totalweight of the catalyst, applied to a support, where from 10 to 50% ofthe pore volume of the support is formed by macropores having a porediameter in the range from 50 nm to 10,000 nm and from 50 to 90% of thepore volume of the support is formed by mesopores having a pore diameterin the range from 2 to 50 nm, where the sum of the pore volumes adds upto 100%, is excluded.
 2. A process as defined in claim 1, wherein thecatalyst comprises as active metal at least one metal of transitiongroup VIII of the Periodic Table either alone or together with at leastone metal of transition group I or IV of the Periodic Table applied to asupport, where the support has a mean pore diameter of at least 50 nmand a BET surface area of at most 30 m²/g and the amount of the activemetal is from 0.01 to 30% by weight, based on the total weight of thecatalyst.
 3. A process as defined in claim 1, wherein the catalystcomprises as active metal at least one metal of transition group VIII ofthe Periodic Table either alone or together with at least one metal oftransition group I or VII of the Periodic Table in an amount of from0.01 to 30% by weight, based on the total weight of the catalyst,applied to a support, where from 10 to 50% of the pore volume of thesupport is formed by macropores having a pore diameter in the range from50 nm to 10,000 nm and from 50 to 90% of the pore volume of the supportis formed by mesopores having a pore diameter in the range from 2 to 50nm, where the sum of the pore volumes adds up to 100%.
 4. A process asdefined in claim 1, wherein the catalyst comprises as active metal atleast one metal of transition group VIII of the Periodic Table eitheralone or together with at least one metal of transition group I or VIIof the Periodic Table in an amount of from 0.01 to 30% by weight, basedon the total weight of the catalyst, applied to a support, where thesupport has a mean pore diameter of at least 0.1 im and a BET surfacearea of at most 15 m²/g.
 5. A process as defined in claim 1, wherein thebenzenepolycarboxylic acid or the derivative thereof is selected fromthe group consisting of monoalkyl and dialkyl esters of phthalic acid,terephthalic acid and isophthalic acid, monoalkyl, dialkyl and trialkylesters of trimellitic acid, trimesic acid and hemimellitic acid,monoalkyl, dialkyl, trialkyl and tetraalkyl esters of pyromellitic acid,where the alkyl groups can be linear or branched and each have from 3 to18 carbon atoms, anhydrides of phthalic acid, trimellitic acid andhemimellitic acid, pyromellitic dianhydride and mixtures of two or morethereof.
 6. A process as defined in claim 2, wherein thebenzenepolycarboxylic acid or the derivative thereof is selected fromthe group consisting of monoalkyl and dialkyl esters of phthalic acid,terephthalic acid and isophthalic acid, monoalkyl, dialkyl and trialkylesters of trimellitic acid, trimesic acid and hemimellitic acid,monoalkyl, dialkyl, trialkyl and tetraalkyl esters of pyromellitic acid,where the alkyl groups can be linear or branched and each have from 3 to18 carbon atoms, anhydrides of phthalic acid, trimellitic acid andhemimellitic acid, pyromellitic dianhydride and mixtures of two or morethereof.
 7. A process as defined in claim 3, wherein thebenzenepolycarboxylic acid or the derivative thereof is selected fromthe group consisting of monoalkyl and dialkyl esters of phthalic acid,terephthalic acid and isophthalic acid, monoalkyl, dialkyl and trialkylesters of trimellitic acid, trimesic acid and hemimellitic acid,monoalkyl, dialkyl, trialkyl and tetraalkyl esters of pyromellitic acid,where the alkyl groups can be linear or branched and each have from 3 to18 carbon atoms, anhydrides of phthalic acid, trimellitic acid andhemimellitic acid, pyromellitic dianhydride and mixtures of two or morethereof.
 8. A process as defined in claim 4, wherein thebenzenepolycarboxylic acid or the derivative thereof is selected fromthe group consisting of monoalkyl and dialkyl esters of phthalic acid,terephthalic acid and isophthalic acid, monoalkyl, dialkyl and trialkylesters of trimellitic acid, trimesic acid and hemimellitic acid,monoalkyl, dialkyl, trialkyl and tetraalkyl esters of pyromellitic acid,where the alkyl groups can be linear or branched and each have from 3 to18 carbon atoms, anhydrides of phthalic acid, trimellitic acid andhemimellitic acid, pyromellitic dianhydride and mixtures of two or morethereof.
 9. A process as defined in claim 1, wherein the supportcomprises activated carbon, silicon carbide, aluminum oxide, silicondioxide, titanium dioxide, zirconium dioxide, magnesium oxide, zincoxide or a mixture of two or more thereof.
 10. A process as defined inclaim 2, wherein the support comprises activated carbon, siliconcarbide, aluminum oxide, silicon dioxide, titanium dioxide, zirconiumdioxide, magnesium oxide, Zinc oxide or a mixture of two or morethereof.
 11. A process as defined in claim 3, wherein the supportcomprises activated carbon, silicon carbide, aluminum oxide, silicondioxide, titanium dioxide, zirconium dioxide, magnesium oxide, zincoxide or a mixture of two or more thereof.
 12. A process as defined inclaim 4, wherein the support comprises activated carbon, siliconcarbide, aluminum oxide, silicon dioxide, titanium dioxide, zirconiumdioxide, magnesium oxide, zinc oxide or a mixture of two or morethereof.
 13. A process as defined in claim 1, wherein the hydrogenationis carried out in the presence of a solvent or diluent.
 14. The processof claim 1, wherein the hydrogenation is carried out continuously. 15.The process of claim 2, wherein the support comprises activated carbon,silicon carbide, aluminum oxide, silicon dioxide, titanium dioxide,zirconium dioxide, magnesium oxide, zinc oxide or a mixture of two ormore thereof.
 16. The process claim 3, wherein the support comprisesactivated carbon, silicon carbide, aluminum oxide, silicon dioxide,titanium dioxide, zirconium dioxide, magnesium oxide, zinc oxide or amixture of two or more thereof.
 17. The process claim 4, wherein thesupport comprises activated carbon, silicon carbide, aluminum oxide,silicon dioxide, titanium dioxide, zirconium dioxide, magnesium oxide,zinc oxide or a mixture of two or more thereof.
 18. A plastics productcontaining a cyclohexanedicarboxylic ester according to claim 12 or acyclohexanetricarboxylic ester or a mixture of two or more thereof as aplasticizer.
 19. A plastics product containing a cyclohexanedicarboxylicester according to claim 3 or a cyclohexanetricarboxylic ester or amixture of two or more thereof as a plasticizer.
 20. A plastics productcontaining a cyclohexanedicarboxylic ester according to claim 4 or acyclohexanetricarboxylic ester or a mixture of two or more thereof as aplasticizer.
 21. A plastics product containing a cyclohexanedicarboxylicester according to claim 1 or a cyclohexanetricarboxylic ester or amixture of two or more thereof as a plasticizer.